Polycarbonate type nonionic surfactants

ABSTRACT

Polycarbonate type nonionic surfactant compositions comprising monohydroxy alcohols capped with polycarbonate groups. More specifically, the surfactant compositions comprise aliphatic, nonaromatic cycloaliphatic or aromatic alcohols which have been capped with block polycarbonate groups formed by the reaction of the alcohols with ethylene carbonate in the presence of an alkali metal salt catalyst. The surfactant properties of the compositions may be varied by first reacting the alcohols with ethylene oxide to form a block polyether group cap on the alcohols before the reaction with ethylene carbonate or by further reacting the polycarbonate capped alcohols with ethylene oxide to form a terminal polyether block group. The surfactants formed are a random distribution mixture of compositions wherein 2 to 20 moles of ethylene carbonate and 3 to 50 moles of ethylene oxide per mole of the alcohols are reacted together.

CROSS-REFERENCE TO RELATED APPLICATION

This is a division of application Ser. No. 177,030, filed Aug. 11, 1980,now U.S. Pat. No. 4,330,481, which in-turn is a division of applicationSer. No. 973,211, filed Dec. 26, 1978, now abandoned.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

This invention relates to nonionic surfactants and methods for makingthe same, with particular reference to nonionic surfactant compositionscomprising monohydroxy alcohols capped with a polycarbonate.

(2) Brief Description of the Prior Art

In many industrial and household cleaning applications it is desirableor necessary to use a surfactant in the cleaning formulations to achievesatisfactory wetting and cleansing. Furthermore, in many of theseindustrial and household applications it is necessary to maintain a lowlevel of foam during the cleaning operation. For example, surfactantsthat produce excessive foaming may be unsuitable in an industrial spraymetal cleaning operation or for use as an active ingredient indetergents and rinse aids for household mechanical dishwashers.

One type of nonionic surfactant known in the art is the fatty acid esterof an alcohol ethoxylate, which ester is produced by condensing ethyleneoxide with a detergent range alcohol, and then reacting such ethoxylatedalcohol with fatty acids containing from 8 to 18 carbon atoms, or withthe chlorides of such acids. Surfactants produced in this manner aredescribed in U.S. Pat. No. 1,970,578 which teaches such surfactants ashaving excellent wetting, foaming and cleansing properties. However,surfactants of this type would not be satisfactory for uses where thesuppression of foam is important.

Another type of nonionic surfactant known in the art is described inU.S. Pat. No. 3,539,518 which teaches a low foam, nonionic surfactantcomposition consisting essentially of a straight chain acyl group of 1to 5 carbon atoms capped on an alcohol ethoxylate. More specifically thelow foam surfactant composition consists of analkoxypolyethoxycarboxylate compound which is produced by condensingethylene oxide on an alcohol having 4 to 20 carbon atoms using meanswell known to the art, and then reacting this ethoxylate with a straightchain alkanoic acid having 1 to 5 carbon atoms or with the acyl halideor the anhydride of such acid.

SUMMARY

In general, the present invention provides new low foam, nonionic,polycarbonate type surfactant compositions and methods for producing thesame. More specifically, the surfactant compositions comprise compoundsrepresented by the following structural formulas: ##STR1## where R is analiphatic, non-aromatic cycloaliphatic or aromatic group, y is a numberfrom 1 to 10 and x is a number from 3 to 50.

In general, the process for producing the above surfactant compositionscomprises reacting ethylene carbonate and a monohydroxy alcohol in thepresence of an alkali metal salt catalyst at a temperature of about 130°C. to about 210° C. The monohydroxy alcohol may be capped with ethyleneoxide before reacting it with ethylene carbonate or the reaction productof the ethylene carbonate/monohydroxy alcohol reaction may be furtherreacted with ethylene oxide to provide surfactants having differentphysical properties. The hydroxyethylation reaction of the alcohol orpolycarbonate reaction product with ethylene oxide can be easilyaccomplished by using a basic catalyst, i.e. KOH, at a temperature ofabout 90° C. to about 120° C.

The reaction of the monohydroxy alcohol or ethoxylated alcohol withethylene carbonate is represented by the following equations. ##STR2##The above equations illustrate that 50% of the available CO₂ in theethylene carbonate is lost as a result of the formation of the carbonateintermediate illustrated by the first equation. Thus, the theoreticalmaximum yield of the polycarbonate block portion in the surfactantcompositions is only 50% of the CO₂ available in the original ethylenecarbonate reactant. Moreover, it is believed that the ethylenecarbonate/alcohol reaction is initiated by an ethoxy ether radicalresulting from the decomposition of ethylene carbonate to ethylene oxideand CO₂. This ethoxy ether free radical initiation of thepolycarbonate/alcohol reaction appears to be accurate since only about38% to 43% of the CO₂ in the ethylene carbonate is normally retained asa carbonate radical in the final surfactant compositions.

Generally, about 2 to 20 moles, and more preferably about 3 to 10 moles,of ethylene carbonate per mole of monohydroxy alcohol or ethoxylatedmonohydroxy alcohol are reacted together to provide the hydrophobicproperties in the final surfactant compositions. Also, about 3 to 50moles, and preferably about 3 to 10 moles, of ethylene oxide per mole ofmonohydroxy alcohol or polycarbonate capped monohydroxy alcohol arereacted together to provide the hydrophilic properties in the finalsurfactant compositions.

The temperature of the ethylene carbonate/alcohol reaction is maintainedbetween about 130° C. to about 210° C., and preferably between about140° C. and about 170° C. A reaction temperature below 130° C. is notdesirable since the formation of the polycarbonate block portion of thesurfactant compositions is extremely slow at such low temperatures.Reaction temperatures above about 210° C. are also undesirable sinceethylene carbonate will decompose into ethylene oxide and CO₂ at theseelevated temperatures and the more reactive hydroxyethylation orpolyether reactions will occur.

In order to form the polycarbonate block portion of the surfactantcompositions, it is necessary that the ethylene carbonate/alcoholreaction be run in the presence of an alkali metal salt catalyst.Examples of useful alkali metal salt catalyst are sodium stannate,potassium stannate, sodium carbonate, potassium carbonate, sodiumhydroxide, potassium hydroxide, the sodium alkoxide of the monohydroxyalcohol and the potassium alkoxide of the monohydroxy alcohol. Sodiumstannate has been found to be a particularly effective catalyst sincehigh yields and low reaction time were obtained when it was used.

In view of the preceding discussion, it will be appreciated that thepolycarbonate type surfactant products produced by this invention have,in all probability, some random ether radicals disposed within thepolycarbonate block portion of the products since the theoretical 50percent CO₂ retention in the products is normally not achieved duringthe ethylene carbonate/alcohol reaction. Furthermore, it will beappreciated that the surfactant products are not a single compound ineach instance but are a mixture of compounds of different molecularweights characterized by an average molecular weight depending on thetermination point of the ether and/or carbonate blocks in each molecule.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description illustrates the manner in which the principlesof the invention are applied but are not to be construed as limiting thescope of the invention. The following examples demonstrate thepreparation of the polycarbonate type surfactants in accordance with thepresent invention.

EXAMPLE 1

A stirred reaction mixture of 2640 grams (30 moles) of ethylenecarbonate, 558 grams (3 moles) of n-dodecanol and 12.0 grams (0.056moles) of sodium stannate was heated to 170° C. for 24 hours in areaction vessel under a nitrogen atmosphere. The mixture was then cooledto 130° C. and 30 grams of finely divided magnesium silicate and 60grams of celite clay were added to purify the mixture. The mixture wascontinuously stirred at 130° C. for an additional 21 hours. At thispoint, the reaction product mixture was permitted to cool and was thenfiltered to remove the magnesium silicate and celite clay. 2000 grams ofa pale yellow, transparent, viscous liquid reaction product was obtainedwhich retained about 40 weight percent of the available CO₂ in theethylene carbonate as a carbonate radical in the reaction product asdetermined by nuclear magnetic resonance spectral analysis.

EXAMPLE 2

A stirred reaction mixture of 44 grams (0.5 moles) of ethylenecarbonate, 18.4 grams (0.1 moles) of cyclododecanol and 0.2 grams (0.001moles) of sodium stannate was heated to 170° C. for 22 hours in areaction vessel under a nitrogen atmosphere. The mixture was then cooledto 130° C. and 0.5 grams of magnesium silicate and 1.0 grams of celiteclay were added to purify the mixture. The mixture was continuouslystirred at 130° C. for an additional one hour. The reaction productmixture was permitted to cool and was then filtered to remove themagnesium silicate and celite clay. 35.1 grams of a pale yellow,transparent, viscous liquid reaction product was obtained whichsolidified on standing. About 40 weight percent of the available CO₂ inthe ethylene carbonate was retained as a carbonate radical in theproduct.

EXAMPLE 3

The reaction conditions of Examples 1 and 2 were duplicated except thata mixture of 44 grams (0.5 moles) of ethylene carbonate, 20 grams (0.091moles) of 4-nonylphenol and 0.2 grams (0.001 moles) of sodium stannatewas reacted at 170° C. for 18 hours. The temperature of the mixture wasreduced to 130° C., 1 gram of magnesium silicate and 1 gram of celiteclay were added to the mixture and stirring was continued for one hourbefore cooling and filtering the reaction product. About 33 weightpercent of the available CO₂ in the ethylene carbonate was retained as acarbonate radical in the reaction product.

EXAMPLE 4

The reaction conditions of Examples 1 and 2 were again duplicated exceptthat a mixture of 44 grams (0.5 moles) of ethylene carbonate, 4.7 grams(0.025 moles) of n-dodecanol and 0.5 grams (0.002 moles) of sodiumstannate was reacted at 150° C. for 40 hours. 30.3 grams of a yellow,transparent, viscous liquid reaction product was obtained afterpurification and filtration as in Example 3. 41 weight percent of theavailable CO₂ was retained as a carbonate radical in the reactionproduct.

EXAMPLE 5

The reaction conditions of Examples 1 and 2 were again duplicated exceptthat a mixture of 44 grams (0.5 moles) of ethylene carbonate, 5 grams(0.025 moles) of 2,4,6,8-tetramethyl-1-nonanol and 0.2 grams (0.001moles) of sodium stannate was reacted at 150° C. for 20 hours. 26.4grams of reaction product was obtained after purification and filtrationas in Example 3. 40 weight percent of the available CO₂ was retained asa carbonate radical in the reaction product.

EXAMPLE 6

The reaction conditions of Examples 1 and 2 were again duplicated exceptthat a mixture of 44 grams (0.5 moles) of ethylene carbonate, 6.3 grams(0.034 moles) of n-dodecanol and 0.01 grams (0.0001 moles) of potassiumcarbonate was reacted at 135° C. for 24 hours. The temperature of themixture was then raised to 165° C. and reacted for an additional 44hours. 26.9 grams of a dark brown, transparent, viscous liquid reactionproduct was obtained after purification and filtration as in Example 3.19 weight percent of the available CO₂ was retained as a carbonateradical in the reaction product.

EXAMPLE 7

37.3 grams (0.2 moles) of n-dodecanol and about 0.05 grams (0.002 moles)of sodium metal were mixed in a reaction vessel at 100° C. until thesodium dissolved. 88.1 grams (1.0 moles) of ethylene carbonate was addedto the reaction vessel and the stirred mixture was heated to 200° C. andmaintained at that temperature for 2 hours. 83.2 grams of a pale yellow,transparent, viscous liquid reaction product was obtained afterpurification and filtration as in Example 3.

EXAMPLE 8

A stirred reaction mixture of 22 grams (0.25 moles) of ethylenecarbonate, 16.6 grams (0.05 moles) of a mixture of n-dodecyl andn-tetradecyl triethoxylates (approximately 50/50 mole percent mixture)and 0.2 grams (0.001 moles) of sodium stannate was heated to 150° C. for17 hours in a reaction vessel under a nitrogen atmosphere. 24.1 grams ofa pale yellow, transparent, viscous liquid reaction product was obtainedafter purification and filtration as in Example 3.

EXAMPLE 9

A stirred reaction mixture of 44 grams (0.5 moles) of ethylenecarbonate, 23.6 grams (0.05 moles) of a mixture of n-dodecyl andn-tetradecyl hexaethoxylates (approximately 50/50 mole percent) and 0.2grams (0.001 moles) of sodium stannate was heated to 150° C. for 24hours. 48.1 grams of a pale yellow, transparent, viscous liquid reactionproduct was obtained after purification and filtration as in Example 3.

EXAMPLE 10

27 grams (0.31 moles) of ethylene carbonate, 53.0 grams (0.10 moles) of2,4,6,8-tetramethyl-1-nonyl octaethoxylate and 0.2 grams (0.001 moles)of sodium stannate were heated to 150° C. for 20 hours in a stirredreaction vessel as in Example 8. 64.2 grams of a pale yellow,transparent, viscous liquid reaction product was obtained afterpurification and filtration as in Example 3.

EXAMPLE 11

440 grams (5 moles) of ethylene carbonate, 530 grams (0.96 moles) of2,4,6,8-tetramethyl-1-nonyl octaethoxylate and 2 grams (0.01 moles) ofsodium stannate were heated to 160° C. for 24 hours in a stirredreaction vessel under a nitrogen atmosphere. The mixture was then cooledto 110° C., 10 grams of magnesium silicate and 10 grams of celite claywere added and the mixture was stirred for one hour. After filtration,703 grams of a pale yellow, transparent, viscous liquid reaction productwas obtained.

EXAMPLE 12

15.1 grams (0.17 moles) of ethylene carbonate, 17.1 grams (0.0087 moles)of tertrary octylphenol capped with 40 moles of ethylene oxide per moleof alcohol and 0.2 grams (0.001 moles) of sodium stannate were heated to160° C. for 12 hours in a stirred reaction vessel as in Example 8. 10.7grams of a tan solid reaction product was obtained after purificationand filtration as in Example 3.

EXAMPLE 13

The reaction conditions of Example 5 were duplicated except that amixture of 44 grams (0.5 moles) of ethylene carbonate, 20 grams (0.1moles) of 2,4,6,8-tetramethyl-1-nonanol and 0.2 grams (0.001 moles) ofsodium stannate was reacted at 150° C. for 20 hours. The reactionproduct was purified and filtered as in Example 3. 20 grams (0.038moles) of this reaction product and 0.1 grams (0.0018 moles) ofpotassium hydroxide were placed in a reaction vessel and heated to 110°C. 7.5 grams (0.17 moles) of ethylene oxide were then added to thereaction vessel and the mixture was continuously stirred for 16 hours.23.5 grams of a pale yellow, transparent, viscous liquid reactionproduct were obtained after purification and filtration as in Example 3.

EXAMPLE 14

The reaction conditions of Example 5 were again duplicated except that amixture of 44 grams (0.5 moles) of ethylene carbonate, 10 grams (0.05moles) of 2,4,6,8-tetramethyl-1-nonanol and 0.2 grams (0.001 moles) ofsodium stannate was reacted at 150° C. for 20 hours. 20 grams (0.023moles) of this reaction product, 5 grams (0.114 moles) of ethylene oxideand 0.1 grams (0.0018 moles) of potassium hydroxide were continuouslystirred at 110° C. for 16 hours in a reaction vessel. 25.5 grams of apale yellow, transparent, viscous liquid reaction product were obtainedafter purification and filtration as in Example 3.

The following Table 1 illustrates the mole ratios of ethylene carbonateand ethylene oxide reacted with each mole of alcohol and the catalystused for the above examples.

                  TABLE I                                                         ______________________________________                                                                     Moles Moles Moles                                Example                                                                              ROH.sup.1    Catalyst EO.sup.2                                                                            EC.sup.3                                                                            EO                                   ______________________________________                                        1      C.sub.12 OH  Na.sub.2 SnO.sub.3                                                                     --    10    --                                   2      Cyc.C.sub.12 OH                                                                            Na.sub.2 SnO.sub.3                                                                     --    5     --                                           ##STR3##    Na.sub.2 SnO.sub.3                                                                     --    5.5   --                                   4      C.sub.12 OH  Na.sub.2 SnO.sub.3                                                                     --    20    --                                   5      C.sub.13 OH  Na.sub.2 SnO.sub.3                                                                     --    20    --                                   6      C.sub.12 OH  K.sub.2 CO.sub.3                                                                       --    14.7  --                                   7      C.sub.12 OH  Na       --    5     --                                   8      C.sub.12 /C.sub.14OH                                                                       Na.sub.2 SnO.sub.3                                                                     3     5     --                                   9      C.sub.12 /C.sub.14OH                                                                       Na.sub.2 SnO.sub.3                                                                     6     10    --                                   10     C.sub.13 OH  Na.sub.2 SnO.sub.3                                                                     8     3     --                                   11     C.sub.13 OH  Na.sub.2 SnO.sub.3                                                                     8     5     --                                   12                                                                                    ##STR4##    Na.sub.2 SnO.sub.3                                                                     40    20    --                                   13     C.sub.13 OH  KOH      --    5     4.5                                  14     C.sub.13 OH  KOH      --    10    4.9                                  ______________________________________                                         .sup.1 Monohydroxy Alcohol                                                    .sup.2 Ethylene Oxide                                                         .sup.3 Ethylene Carbonate                                                

The following Table 2 illustrates the surfactant properties for thereaction products of the above examples.

                  TABLE 2                                                         ______________________________________                                        Ex-  Surface  Interfacial                                                                             Foam Height-                                                                           Wetting                                                                              Cloud                                 am-  Tension.sup.2                                                                          Tension.sup.3                                                                           Cms.sup.4                                                                              Time.sup.5                                                                           Pt..sup.6                             ple.sup.1                                                                          dynes/cm dynes/cm  Initial                                                                             Final                                                                              secs   °C.                          ______________________________________                                        1    28.2     1.3       1.5   0.5  >300   <25                                 2    37.4     1.0       0.5   0.2  >300   <25                                 3    31.3     9.4       0.8   0.7  >300   Insoluble                           4    31.8     1.3       *5.5  *3.0 *120   <25                                 5    32.7     1.6       *4.6  *0.8 >300   <25                                 6    33.3     5.8       19.6  8.9  75     <25                                 7    28.8     1.0       5.6   1.8  85     <25                                 8    31.7     2.2       23.0  6.6  45      35                                 9    29.8     1.8       6.1   2.3  61     --                                  10   27.5     1.1       8.6   3.8  36      18                                 11   26.8     1.7       6.0   1.6  40      24                                 12   34.3     8.9       26.9  12.2 >300   --                                  13   26.8     2.4       7.6   3.3  81      <5                                 14   29.6     1.2       8.4   3.8  66      <5                                 ______________________________________                                         .sup.1 0.1 weight percent concentration in deionized water. Numbers marke     with * are 1.0 weight percent concentration in deionized water.                .sup.2 ASTM D1331 test procedure.                                            .sup.3 ASTM D1331 test procedure.                                             .sup.4 Foam height was determined using the Hamilton Blender (Model No.       6363) Foam Test. 250 ml. of a 0.1% by weight surfactant/water solution wa     whipped at low speed for one minute. The solution and foam were poured        into a standard 500 ml. graduated cylinder having a 4.7 centimeter            diameter. The foam height was measured immediately and after five minutes     .sup.5 The Syndrome Tape Modification of the DravesClarkson wetting test      using a nineinch strip of unmercerized natural cotton cloth tape attached     to a one gram hook which in turn is attached to a forty gram weight by        thread was used to determine wetting time. The solution concentration was     0.1% by weight surfactant in deionized water. The arrangement was dropped     into a 500 ml. of the surfactant solution. When the tape was wetted, it       dropped to the bottom of the graduated cylinder indicating the wetting        time.                                                                         .sup.6 ASTM D2024 test procedure except 0.1% concentration used in place      of 1.0% concentration.                                                   

While certain representative embodiments have been shown in detail forthe purpose of illustrating the invention, it will be apparent to thoseskilled in the art that various changes and modifications can be madewithout departing from the spirit and scope of the invention.

What is claimed is:
 1. A process for the preparation of polycarbonatetype surfactants comprising the steps of: (a) reacting ethylenecarbonate and monohydroxy alcohol in the presence of an alkali metalsalt catalyst at a temperature of about 130° C. to about 210° C. to forma reaction product, a (b) further reacting the reaction product of step(a) with ethylene oxide.
 2. The process of claim 1 wherein about 2 to 20moles of ethylene carbonate per mole of said monohydroxy alcohol arereacted together.
 3. The process of claim 2 wherein about 3 to 50 molesof ethylene oxide per mole of the reaction product formed in step (a)are reacted together.
 4. The process of claim 3 wherein about 3 to 10moles of ethylene oxide per mole of the reaction product formed in step(a) are reacted together.
 5. The process of claim 2 wherein about 3 to10 moles of ethylene carbonate per mole of said monohydroxy alcohol arereacted together.
 6. The process of claim 5 wherein about 3 to 50 molesof ethylene oxide per mole of the reaction product formed in step (a)are reacted together.
 7. The process of claim 6 wherein about 3 to 10moles of ethylene oxide per mole of the reaction product formed in step(a) are reacted together.